constant velocity joint of the three-bar design

Abstract

In a constant velocity joint of tripod design (1), a groove-orthogonal cross-sectional shape of a cover surface (13) of a raceway groove (10) of an outer ring (2) is a line shape that passes through a highest central point (P1, P11, P12), a highest point (P2, P13, P15) of a positive rotation edge, and a highest point (P3, P14, P16) of a negative rotation edge. The highest central point (P1, P11, P12) is a point when a roller (4) is inclined by a predetermined angle of inclination (θp2). The highest point (P2, P13, P15) of the positive rotation edge is a point when the roller (4) rolls in a positive direction by a predetermined rolling angle (θr11). The highest point (P3, P14, P16) of the negative rotation edge is a point when the roller (4) rolls in a negative direction by a predetermined rolling angle (θr12).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a tripod type constant velocity joint. STATE OF THE ART

[0002] A tripod-type constant velocity joint described in Patent Document 1 is designed to prevent the tilting of rollers (rolling elements) by means of raceway grooves in an outer ring. A portion of the ceiling surface of the raceway groove of the outer ring comes into contact with the end surface of the roller (roller end surface), thereby preventing the roller from tilting. State of the art documentsPatent documents

[0003] Patent Document 1: Unexamined Japanese Patent Application Publication No. 2016-130533 (JP 2016-130533 A) SUMMARY OF THE INVENTIONProblem to be solved by the invention

[0004] It is known that rollers (rolling elements) of a tripod-type constant velocity joint can tilt (lean) or roll during joint operation. However, in the tripod-type constant velocity joint described in Patent Document 1, the tilting of the roller is limited (prevented) by the ceiling surface of the raceway groove. Therefore, when the roller is tilted or rolled, friction is generated by contact between the ceiling surface of the raceway groove of the outer ring and the end surface of the roller. This friction causes a force effect / constraining force, which generates vibration in the tripod-type constant velocity joint (causes it to vibrate).

[0005] The present disclosure has been made in view of such a problem and provides a tripod type constant velocity joint that can reduce or prevent generation of a constraining force by preventing a roller end surface from coming into contact with a ceiling surface of a raceway groove of an outer ring at least within a predetermined angular range. Means to solve the problem

[0006] One aspect of the present disclosure is a tripod-type constant velocity joint comprising: an outer ring having a plurality of raceway grooves extending in an axial direction; a tripod having a plurality of tripod shaft portions extending radially outward; and rollers (rolling elements) fitted externally onto the tripod shaft portions and configured to roll in the raceway grooves.

[0007] The raceway groove has a first raceway surface forming a groove side surface, a second raceway surface forming another groove side surface, and a ceiling surface forming a groove bottom surface.

[0008] The roller has a roller outer peripheral surface configured to roll on the first raceway surface or the second raceway surface, and a roller end surface that is an axial end surface of the roller facing the ceiling surface.

[0009] A point located on a center axis of the roller and away from a center axis of the outer ring on a contour line obtained by projecting the roller end surface in the axial direction of the outer ring when the roller is inclined (tilted) by a predetermined inclination angle (tilt angle) is defined as a highest central point.

[0010] A boundary point between the roller outer peripheral surface and the roller end surface located away from the center axis of the outer ring on a contour line obtained by projecting the roller in the axial direction of the outer ring when the roller rolls in a positive direction by a predetermined rolling angle is defined as a highest point of a positive rotation edge.

[0011] A boundary point between the roller outer peripheral surface and the roller end surface located away from the center axis of the outer ring on a contour line obtained by projecting the roller in the axial direction of the outer ring when the roller rolls in a negative direction by a predetermined rolling angle is defined as a highest point of a negative turning edge.

[0012] A groove-orthogonal cross-sectional shape (cross-sectional shape orthogonal to the groove) of the ceiling surface is a line shape passing through the highest central point, the highest point of the positive turning edge and the highest point of the negative turning edge. Effects of the invention

[0013] In the tripod-type constant velocity joint of the above aspect, the groove-orthogonal cross-sectional shape of the ceiling surface of the raceway groove of the outer ring is the line shape passing through the highest central point, the highest point of the positive rotation edge, and the highest point of the negative rotation edge. The highest central point is a point obtained from the contour line of the roller end surface when the roller tilts or is inclined by the predetermined inclination angle. The highest point of the positive rotation edge is a point obtained from the contour line of the roller when the roller rolls in the positive direction by the predetermined pitch angle. The highest point of the negative rotation edge is a point obtained from the contour line of the roller when the roller rolls in the negative direction by the predetermined pitch angle.

[0014] Therefore, the roller can be prevented from coming into contact with the ceiling surface of the raceway groove of the outer ring when the roller tilts at an angle smaller than the predetermined inclination angle and rolls at an angle smaller than the predetermined pitch angle. In this way, the roller end surface can be prevented from coming into contact with the ceiling surface of the raceway groove of the outer ring when the roller tilts and rolls at least within the predetermined angle ranges. Thus, the generation of the force effect / constraining force can be prevented.

[0015] Specifically, the highest central point is a point located on the center axis of the roller and away from the center axis of the outer ring on the contour line obtained by projecting the roller end surface in the axial direction of the outer ring when the roller is tilted by the predetermined tilt angle. The highest point of the positive rotation edge is a boundary point between the roller outer peripheral surface and the roller end surface, located away from the center axis of the outer ring on the contour line obtained by projecting the roller in the axial direction of the outer ring when the roller rolls in the positive direction by the predetermined pitch angle.The highest point of the negative rotation edge is a boundary point between the roller outer peripheral surface and the roller end surface located away from the center axis of the outer ring on the contour line obtained by projecting the roller in the axial direction of the outer ring when the roller rolls in the negative direction by the predetermined rolling angle.

[0016] In this way, the shape of the crown surface is defined, taking into account which positions on the groove-orthogonal cross-sectional shape of the crown surface approach which points on the roller during both tilting (tilting) and rolling. This design prevents the roller end surface from coming into contact with the crown surface of the raceway groove of the outer ring when the roller tilts and rolls at least within the predetermined angular ranges. Thus, the generation of the force effect / constraint force can be prevented.

[0017] As described above, according to the above aspect, it is possible to provide the tripod type constant velocity joint which can prevent the generation of the urging force by preventing the roller end surface from coming into contact with the ceiling surface of the raceway groove of the outer ring at least within the predetermined angular range.

[0018] Reference numerals in parentheses in the claims represent the corresponding relationships to specific devices described in embodiments described below and are not intended to limit the technical scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Fig. 1 is a diagram of a tripod type constant velocity joint of a first embodiment as viewed in an axial direction, showing a case where a joint angle is 0° and showing only a portion of a raceway groove of an outer ring. Fig. 2 is a sectional view along a line II-II in Fig. 1 and is a partial axial sectional view of the tripod type constant velocity joint. Fig. 3 is a sectional view taken along a line III-III in Fig. 2 and is a partial radial sectional view of the tripod type constant velocity joint. Fig. 4 is a partial view of the tripod type constant velocity joint as viewed in the axial direction when the joint angle is θp1 and a roller is inclined (tilted) by an inclination angle (tilt angle) θp1. Fig. 5 is a sectional view along a line VV in Fig. 4 and is a partial axial sectional view of the tripod type constant velocity joint when the joint angle is θp1. Fig. 6 is a partial view of the tripod type constant velocity joint as viewed in the axial direction when the joint angle is 0° and the roller rolls in a positive direction by a rolling angle θr1. Fig. 7 is a partial view of the tripod type constant velocity joint as viewed in the axial direction when the joint angle is 0° and the roller rolls in a negative direction by a rolling angle θr2. Fig. 8 is a partial axial sectional view of the tripod type constant velocity joint when the joint angle is θp2 and the roller is inclined by an inclination angle θp2. Fig. 9 is a diagram showing only the outer ring and the roller as viewed from a left side of Fig. 7 shows, that is, in the axial direction of the outer ring. Fig. 10 is a partial view of the tripod type constant velocity joint as viewed in the axial direction when the joint angle is 0° and the roller rolls in the positive direction by a rolling angle θr11. Fig. 11 is a partial view of the tripod type constant velocity joint as viewed in the axial direction when the joint angle is 0° and the roller rolls in the negative direction by a rolling angle θr12. Fig. 12 is a diagram showing a groove-orthogonal cross-sectional shape of a ceiling surface of the raceway groove of the outer ring. Fig. 13 is a partial view of a tripod type constant velocity joint of a second embodiment as viewed in the axial direction when the roller is inclined by the inclination angle θp2 and comes into contact with a first raceway surface. Fig. 14 is a partial view of the tripod type constant velocity joint of the second embodiment as viewed in the axial direction when the roller is inclined by the inclination angle θp2 and comes into contact with a second raceway surface. Fig. 15 is a partial view of the tripod type constant velocity joint as viewed in the axial direction when the joint angle is 0° and the roller rolls in the positive direction by the rolling angle θr11 and comes into contact with the first raceway surface. Fig. 16 is a partial view of the tripod type constant velocity joint as viewed in the axial direction when the joint angle is 0° and the roller rolls in the negative direction by the rolling angle θr12 and comes into contact with the second raceway surface. Fig. 17 is a diagram showing the groove-orthogonal cross-sectional shape of the ceiling surface of the raceway groove of the outer ring. Fig. 18 is a partial view of a tripod type constant velocity joint of a third embodiment as viewed in the axial direction when the joint angle is 0° and the roller rolls in the positive direction by the rolling angle θr11 and comes into contact with the second raceway surface. Fig. 19 is a partial view of the tripod type constant velocity joint of the third embodiment as viewed in the axial direction when the joint angle is 0° and the roller rolls in the negative direction by the rolling angle θr12 and comes into contact with the first raceway surface. Fig. 20 is a diagram showing the groove-orthogonal cross-sectional shape of the ceiling surface of the raceway groove of the outer ring. Fig. 21 is a diagram showing a groove-orthogonal cross-sectional shape of a ceiling surface of a raceway groove of an outer ring of a tripod type constant velocity joint of a fourth embodiment. MODES FOR CARRYING OUT THE INVENTION (First Embodiment) 1. Design of the Tripod-Type Constant Velocity Joint 1

[0020] The configuration of a tripod type constant velocity joint 1 of the present embodiment will be described below with reference to Fig. 1 to 3. The tripod-type constant velocity joint 1 is used, for example, in a drive shaft or propshaft of a vehicle. The tripod-type constant velocity joint 1 has an outer ring 2, a tripod 3, and rollers (rolling elements) 4.

[0021] The outer ring 2 is formed in a tubular shape with a bottom and has three raceway grooves 10 extending in an axial direction on its inner peripheral surface. The three raceway grooves 10 are positioned at equal intervals in a circumferential direction. Fig. 1 to 3 show only one raceway groove 10. In the following description, a groove-orthogonal cross section (cross section orthogonal to the groove) is a cross section orthogonal to the direction in which the raceway groove 10 extends, and a groove-direction cross section is a cross section in the direction in which the raceway groove 10 extends. A line orthogonal to a center axis Lo of the outer ring 2 and passing through the center of the raceway groove 10 in a groove width direction is defined as a raceway groove center line Lg.

[0022] The raceway groove 10 has a first raceway surface 11 constituting one groove side surface and a second raceway surface 12 constituting the other groove side surface. The first raceway surface 11 and the second raceway surface 12 are opposed to each other (they face each other). The groove-orthogonal cross-sectional shape (cross-sectional shape orthogonal to the groove) of each of the first raceway surface 11 and the second raceway surface 12 is a curved concave shape in the groove-orthogonal cross section of the raceway groove 10. The groove-orthogonal cross-sectional shape of each of the first raceway surface 11 and the second raceway surface 12 is, for example, a Gothic arch shape in which two circular arcs are connected.

[0023] The raceway groove 10 further includes a ceiling surface 13 forming a groove bottom surface. The detailed shape of the ceiling surface 13 will be described below. In the present embodiment, the raceway groove 10 includes a first recessed surface 14 and a second recessed surface 15. The first recessed surface 14 is a portion connecting the first raceway surface 11 and the ceiling surface 13 and is positioned at one groove bottom corner portion. The second recessed surface 15 is a portion connecting the second raceway surface 12 and the ceiling surface 13 and is positioned at the other groove bottom corner portion. The groove-orthogonal cross-sectional shape of each of the first recessed surface 14 and the second recessed surface 15 is a curved concave shape having a smaller radius of curvature than those of the first raceway surface 11, the second raceway surface 12, and the ceiling surface 13.

[0024] The tripod 3 is a component attached to a shaft (not shown) and constitutes an inner component housed in the outer ring 2. The tripod 3 includes a hub portion 21 and three tripod shaft portions 22. The hub portion 21 is formed in a tubular shape and has a keyway formed on its inner peripheral surface so that it can be fitted (attached) to the shaft.

[0025] The tripod shaft portion 22 is a member extending radially outward from the outer peripheral surface of the hub portion 21. The tripod shaft portion 22 is formed in a columnar shape, a spherical shape, etc. For example, the tripod shaft portion 22 formed in the columnar shape may have a circular columnar shape, an elliptical columnar shape, or a composite columnar shape in which a part of a circular column or an elliptical column is formed in a sheet-like shape. In the present embodiment, the columnar cross-sectional shape of the tripod shaft portion 22 includes a pair of convexly curved portions forming an ellipse and straight portions connecting the convexly curved portions.

[0026] The roller 4 is externally fitted (fixed) to the tripod shaft portion 22 and is slidable in the axial direction of the tripod shaft portion 22. The roller 4 rolls in the raceway groove 10 of the outer ring 2 while externally fitted to the tripod shaft portion 22. When torque is transmitted between the roller 4 and the first raceway surface 11, the roller 4 rolls on the first raceway surface 11. When torque is transmitted between the roller 4 and the second raceway surface 12, the roller 4 rolls on the second raceway surface 12.

[0027] As in Fig. 1 and Fig. As shown in Figure 2, the outer shape of the roller 4 includes a roller outer peripheral surface 31, a roller end surface 32, and a roller base surface 33. The roller outer peripheral surface 31 is configured to roll on the first raceway surface 11 or the second raceway surface 12. The roller outer peripheral surface 31 is formed, for example, in a spherical shape centered on a point on a central axis Lr of the roller 4.

[0028] The roller end surface 32 is one of the axial end surfaces of the roller 4 facing the ceiling surface 13. In the present embodiment, the roller end surface 32 includes a circular flat portion 32a and a chamfered portion 32b. The circular flat portion 32a is formed in a disc-like shape centered on the central axis Lr of the roller 4 and parallel to a plane orthogonal to the axis of the roller 4. The chamfered portion 32b is a surface connecting the outer peripheral edge of the circular flat portion 32a and the roller outer peripheral surface 31, and is formed in a partially conical shape inclined with respect to the plane orthogonal to the axis of the roller 4.

[0029] The roller base surface 33 is one of the axial end surfaces of the roller 4, which is opposite to the roller end surface 32. In the present embodiment, the roller base surface 33 is formed in a shape symmetrical to the roller end surface 32. The roller base surface 33 includes a circular flat portion 33a and a chamfered portion 33b. The circular flat portion 33a is formed in a disc shape centered on the central axis Lr of the roller 4 and parallel to the plane orthogonal to the axis of the roller 4. The chamfered portion 33b is a surface connecting the outer peripheral edge of the circular flat portion 33a and the roller outer peripheral surface 31, and is formed in a partially conical shape inclined with respect to the plane orthogonal to the axis of the roller 4.

[0030] The roller 4 can be either a single-roller type or a double-roller type. For example, the single-roller type roller 4 includes an outer roller and a plurality of needle bearings disposed between the outer peripheral surface of the tripod shaft portion 22 and the inner peripheral surface of the outer roller. The double-roller type roller 4 includes an outer roller, an inner roller, and a plurality of needle bearings disposed between the outer roller and the inner roller. The roller 4 can be tiltable (inclinable) or non-tiltable (non-inclinable) with respect to the tripod shaft portion 22.

[0031] In the present embodiment, the roller 4 of the double roller type is applied as shown in Fig. 3. The roller 4 includes an outer roller 41, an inner roller 42, a plurality of needle bearings 43, and snap rings 44, 45. The outer peripheral surface of the outer roller 41 is configured to roll on the first raceway surface 11 and the second raceway surface 12.

[0032] The axial cross-sectional shape of the inner peripheral surface of the inner roller 42 is, for example, a curved shape that is convex radially inward. The inner roller 42 is fitted externally onto the outer peripheral surface of the tripod shaft portion 22 and is tiltable with respect to the tripod shaft portion 22. The plurality of needle bearings 43 are arranged between the inner peripheral surface of the outer roller 41 and the outer peripheral surface of the inner roller 42. The snap rings 44, 45 are snapped onto the outer roller 41 and engage with the inner roller 42 and the plurality of needle bearings 43 to position the inner roller 42 and the plurality of needle bearings 43. 2. Operation of the constant velocity joint 1 of the tripod type

[0033] The operation of the tripod type constant velocity joint 1 is described below with reference to Fig. 4 to 7. As described in Fig. 4 and Fig. As shown in Figure 5, the angle between the center axis Lo of the outer ring 2 and the center axis of the tripod 3 is a joint angle. When the center axis Lr of the roller 4 coincides with the center axis of the shaft portion 22 of the tripod, the angle between the raceway groove center line Lg and the center axis Lr of the roller 4 is the same as the joint angle. Fig. 4 and Fig. 5 show a state where the joint angle is θp1.

[0034] When the joint angle is θp1 and the tripod-type constant velocity joint 1 rotates, a torque is transmitted between the outer ring 2 and the tripod 3 via the roller 4. At this time, the roller 4 rolls on the first raceway surface 11 or the second raceway surface 12 and moves back and forth in the raceway groove 10 while tilting with respect to the raceway groove 10.

[0035] Furthermore, the position on the tripod shaft portion 22 that comes into contact with the roller 4 is shifted in the axial direction of the tripod shaft portion 22. Therefore, the roller 4 rolls in a positive direction as shown in Fig. 6, or rolls in a negative direction, as shown in Fig. 7 is shown. In Fig. 6 is the rolling angle of the rolling in the positive direction θr1. In Fig. 7 is the rolling angle of rolling in the negative direction θr2. The rolling angle θr1 is an angle between the raceway groove centerline Lg and the center axis Lr of the roller 4 during rolling in the positive direction. The rolling angle θr2 is an angle between the raceway groove centerline Lg and the center axis Lr of the roller 4 during rolling in the negative direction.

[0036] A maximum joint angle φ1 of the tripod-type constant velocity joint 1 during straight-ahead travel of the vehicle at a constant speed is an angle that lies in a range of, for example, 4 to 10°. A maximum joint angle φ2 of the tripod-type constant velocity joint 1 during acceleration or deceleration of the straight-ahead travel vehicle can have an angular range that is larger than that of the maximum joint angle φ1. The maximum joint angle φ2 lies, for example, in a range of 6 to 20°. A maximum joint angle φ3 of the tripod-type constant velocity joint 1 during maximum steering can have an angular range that is larger than that of the maximum joint angles φ1, φ2. The maximum joint angle φ3 lies, for example, in a range of 10 to 25°.

[0037] A maximum rolling angle φ11 of the roller 4 during straight-ahead travel of the vehicle at a constant speed is an angle that lies in a range of, for example, 0 to 5°. A maximum rolling angle φ12 of the roller 4 during acceleration or deceleration of the straight-ahead travel of the vehicle lies in a range of, for example, 0 to 5°. A maximum rolling angle φ13 of the roller 4 during maximum steering can have an angular range that is larger than the maximum rolling angles φ11, φ12. The maximum rolling angle φ13 lies, for example, in a range of 0 to 10°. 3. Contour of the groove-orthogonal cross-sectional shape of the ceiling surface 13

[0038] The contour of the groove-orthogonal cross-sectional shape of the cover surface 13 of the raceway groove 10 of the outer ring 2 is shown below with reference to Fig. 8 to 11. The groove-orthogonal cross-sectional shape of the ceiling surface 13 is determined using the shape of the roller 4 when the roller 4 is inclined by a predetermined inclination angle θp2, as shown in Fig. 8. When the roller 4 tilts (is inclined) by the predetermined inclination angle θp2, the roller 4 appears as shown in Fig. 7, as viewed in the axial direction of the outer ring 2. The predetermined inclination angle θp2 is a contact inclination angle. This means that the roller 4 can come into contact with the ceiling surface 13 when the roller 4 tilts by the predetermined angle θp2.

[0039] Furthermore, the groove-orthogonal cross-sectional shape of the ceiling surface 13 is determined using the shape of the roller 4 when the roller 4 rolls in the positive direction by a predetermined rolling angle θr11, as shown in Fig. 10. The groove-orthogonal cross-sectional shape of the ceiling surface 13 is determined using the shape of the roller 4 when the roller 4 rolls in the negative direction by a predetermined rolling angle θr12, as shown in Fig. 11. The predetermined rolling angles θr11, θr12 are contact rolling angles. This means that the roller 4 can come into contact with the ceiling surface 13 when the roller 4 rolls in the positive direction by the predetermined rolling angle θr11 or when the roller 4 rolls in the negative direction by the predetermined rolling angle θr12. The rolling angle θr11 is an angle between the raceway groove centerline Lg and the center axis Lr of the roller 4 during rolling in the positive direction. The rolling angle θr12 is an angle between the raceway groove centerline Lg and the center axis Lr of the roller 4 during rolling in the negative direction.

[0040] The predetermined inclination angle θp2 can be one of the following two types of angles. A first predetermined inclination angle θp2 is set to an angle that is greater than the maximum joint angle φ1 during straight-ahead travel of the vehicle at a constant speed and equal to or less than the maximum joint angle φ2 during acceleration or deceleration of the straight-ahead travel of the vehicle. In this case, the first predetermined inclination angle θp2 is naturally an angle that is less than the maximum joint angle φ3 during maximum steering.

[0041] In this case, the roller 4 does not come into contact with the ceiling surface 13 when the inclination angle of the roller 4 is the maximum joint angle φ1 during straight-line travel of the vehicle at a constant speed. The roller 4 comes into contact with the ceiling surface 13 when the inclination angle of the roller 4 is the maximum joint angle φ2 during acceleration or deceleration of the straight-line travel vehicle. When the inclination angle of the roller 4 changes to increase, the roller 4 comes into contact with the ceiling surface 13 within the range where the inclination angle of the roller 4 is greater than φ1 and equal to or less than φ2.

[0042] A second predetermined inclination angle θp2 is set to an angle that is greater than the maximum joint angle φ2 during acceleration or deceleration of the straight-ahead vehicle and equal to or less than the maximum joint angle φ3 during maximum steering. In this case, the second predetermined inclination angle θp2 is naturally an angle that is greater than the maximum joint angle φ1 during straight-ahead vehicle travel at a constant speed.

[0043] In this case, the roller 4 does not come into contact with the ceiling surface 13 when the inclination angle of the roller 4 is the maximum joint angle φ1 during straight-line travel of the vehicle at the constant speed. Furthermore, the roller 4 does not come into contact with the ceiling surface 13 when the inclination angle of the roller 4 is the maximum joint angle φ2 during acceleration or deceleration of the straight-line travel vehicle. The roller 4 comes into contact with the ceiling surface 13 when the inclination angle of the roller 4 is the maximum joint angle φ3 during maximum steering. When the inclination angle of the roller 4 changes to increase, the roller 4 comes into contact with the ceiling surface 13 within the range where the inclination angle of the roller 4 is greater than φ2 and equal to or less than φ3.

[0044] Since the predetermined roll angles θr11, θr12 correspond to the predetermined pitch angle θp2, the predetermined roll angles θr11, θr12 can be one of the following two types of angles similar to the predetermined pitch angle θp2. The first predetermined roll angles θr11, θr12 are set to angles greater than the maximum roll angle φ11 during straight-ahead travel of the vehicle at a constant speed and equal to or smaller than the maximum roll angle φ12 during acceleration or deceleration of the straight-ahead travel. In this case, the first predetermined roll angles θr11, θr12 are naturally angles smaller than the maximum roll angle φ13 during maximum steering.

[0045] In this case, the roller 4 does not come into contact with the ceiling surface 13 when the rolling angle of the roller 4 is the maximum rolling angle φ11 during straight-line travel of the vehicle at a constant speed. The roller 4 comes into contact with the ceiling surface 13 when the rolling angle of the roller 4 is the maximum rolling angle φ12 during acceleration or deceleration of the straight-line travel vehicle. When the rolling angle of the roller 4 changes to increase, the roller 4 comes into contact with the ceiling surface 13 within the range where the rolling angle of the roller 4 is greater than φ11 and equal to or less than φ12.

[0046] The second predetermined roll angles θr11, θr12 are set to angles greater than the maximum roll angle φ12 during acceleration or deceleration of the straight-ahead vehicle and equal to or less than the maximum roll angle φ13 during maximum steering. In this case, the second predetermined roll angles θr11, θr12 are, of course, angles greater than the maximum roll angle φ11 during the vehicle's straight-ahead travel at a constant speed.

[0047] In this case, the roller 4 does not come into contact with the ceiling surface 13 when the rolling angle of the roller 4 is the maximum rolling angle φ11 during straight-line travel of the vehicle at the constant speed. Furthermore, the roller 4 does not come into contact with the ceiling surface 13 when the pitch angle of the roller 4 is the maximum rolling angle φ12 during acceleration or deceleration of the straight-line travel vehicle. The roller 4 comes into contact with the ceiling surface 13 when the rolling angle of the roller 4 is the maximum rolling angle φ13 during maximum steering. When the rolling angle of the roller 4 changes to increase, the roller 4 comes into contact with the ceiling surface 13 within the range where the rolling angle of the roller 4 is larger than φ12 and equal to or smaller than φ13.

[0048] When the roller 4 is not in contact with the ceiling surface 13, a gap exists between the roller 4 and the ceiling surface 13. Therefore, by increasing the range of the inclination angle in which the roller 4 is not in contact with the ceiling surface 13, the generation of a force action / constraint force in the range where the roller 4 reaches a large inclination angle can be further prevented. By increasing the range of the rolling angle in which the roller 4 is not in contact with the ceiling surface 13, the generation of a force action / constraint force in the range where the roller 4 reaches a large rolling angle can be further prevented.

[0049] As the inclination angle at which the roller 4 is not in contact with the ceiling surface 13 increases, the size of the outer ring 2 increases. Likewise, as the pitch angle at which the roller 4 is not in contact with the ceiling surface 13 increases, the size of the outer ring 2 increases. Therefore, the ranges of the inclination angle and the pitch angle where the roller 4 is not in contact with the ceiling surface 13 are not excessively increased, and the range where the generation of the force action / constraint force can be prevented is minimized. Thus, the effects of reducing and preventing the force action / constraint force can be achieved. 4. Details of the groove-orthogonal cross-sectional shape of the ceiling surface 13

[0050] Details of the groove-orthogonal cross-sectional shape of the ceiling surface 13 are given below with reference to Fig. 9 to 11. As described in Fig. As shown in Fig. 9, a contour line OL1 obtained by projecting the roller end surface 32 in the axial direction of the outer ring 2 when the roller 4 is inclined by the predetermined inclination angle θp2 has a shape indicated by a wide solid line. At this time, the roller 4 is not rolling. In the present embodiment, part of the contour line OL1 is defined by a boundary line between the circular flat portion 32a and the chamfered portion 32b, and the other part of the contour line OL1 is defined by a boundary line between the chamfered portion 32b and the roller outer peripheral surface 31. A point on the contour line OL1 located on the center axis Lr of the roller 4 and away from the center axis Lo of the outer ring 2 is defined as a highest central point P1.

[0051] As in Fig. As shown in FIG. 10, a contour line OL2 obtained by projecting the roller 4 in the axial direction of the outer ring 2 when the joint angle is 0° and the roller 4 rolls in the positive direction through the predetermined pitch angle θr11 has a shape indicated by a wide solid line. Therefore, the contour line OL2 is formed by the roller outer peripheral surface 31, the roller end surface 32, and the roller base surface 33. A boundary point on the contour line OL2 between the roller outer peripheral surface 31 and the roller end surface 32, which is located away from the center axis Lo of the outer ring 2, is defined as a highest point P2 of a positive rotation edge.

[0052] As in Fig. As shown in Fig. 11, a contour line OL2 obtained by projecting the roller 4 in the axial direction of the outer ring 2 when the joint angle is 0° and the roller 4 rolls in the negative direction by the predetermined pitch angle θr12 has a shape indicated by a wide solid line. Therefore, the contour line OL3 is formed by the roller outer peripheral surface 31, the roller end surface 32, and the roller base surface 33. A boundary point on the contour line OL3 between the roller outer peripheral surface 31 and the roller end surface 32, which is located away from the center axis Lo of the outer ring 2, is defined as a highest point P3 of a negative rotation edge.

[0053] As in Fig. As shown in Figure 11, the groove-orthogonal cross-sectional shape of the ceiling surface 13 is a line shape passing through the highest central point P1, the highest point P2 of the positive turning edge, and the highest point P3 of the negative turning edge. Specifically, the groove-orthogonal cross-sectional shape of the ceiling surface 13 is defined by a curved shape 13a connecting the highest central point P1 and the highest point P2 of the positive turning edge, and a curved shape 13b connecting the highest central point P1 and the highest point P3 of the negative turning edge. Each of the curved shapes 13a, 13b may be defined by an ellipse or a circular arc. 5. Effects

[0054] In the tripod-type constant velocity joint 1 of the present embodiment, the groove-orthogonal cross-sectional shape of the ceiling surface 13 of the raceway groove 10 of the outer ring 2 is the line shape passing through the highest central point P1, the highest point P2 of the positive rotation edge, and the highest point P3 of the negative rotation edge. The highest central point P1 is a point obtained from the contour line OL1 of the roller end surface 32 when the roller 4 tilts (inclines) by the predetermined tilt angle θp2. The highest point of the positive rotation edge P2 is a point obtained from the contour line OL2 of the roller 4 when the roller 4 rolls in the positive direction by the predetermined pitch angle θr11. The highest point P3 of the negative turning edge is a point obtained from the contour line OL3 of the roller 4 when the roller 4 rolls by the predetermined rolling angle θr12 in the negative direction.

[0055] Therefore, the roller 4 can be prevented from coming into contact with the ceiling surface 13 of the raceway groove 10 of the outer ring 2 when the roller 4 is tilted (tilted) at an angle smaller than the predetermined tilt angle θp2 and rolls at an angle smaller than the predetermined rolling angles θr11, θr12. In this way, the roller end surface 32 can be prevented from coming into contact with the ceiling surface 13 of the raceway groove 10 of the outer ring 2 when the roller 4 tilts and rolls at least within the predetermined angle ranges. Thus, the generation of the force action / constraining force can be prevented.

[0056] Specifically, the highest central point P1 is a point located on the center axis Lr of the roller 4 and away from the center axis Lo of the outer ring 2 on the contour line OL1 obtained by projecting the roller end surface 32 in the axial direction of the outer ring 2 when the roller 4 is tilted by the predetermined inclination angle θp2. The highest point P2 of the positive rotation edge is a boundary point between the roller outer peripheral surface 31 and the roller end surface 32, located away from the center axis Lo of the outer ring 2 on the contour line OL2 obtained by projecting the roller 4 in the axial direction of the outer ring 2 when the roller 4 rolls in the positive direction by the predetermined pitch angle θr11.The highest point P3 of the negative rotation edge is a boundary point between the roller outer peripheral surface 31 and the roller end surface 32, which is located away from the center axis Lo of the outer ring 2 on the contour line OL3 obtained by projecting the roller 4 in the axial direction of the outer ring 2 when the roller 4 rolls in the negative direction by the predetermined rolling angle θr12.

[0057] In this way, the shape of the ceiling surface 13 is defined, taking into account which positions on the groove-orthogonal cross-sectional shape of the ceiling surface 13 approach which points on the roller 4 during both tilting and rolling. With this design, the roller end surface 32 can be prevented from coming into contact with the ceiling surface 13 of the raceway groove 10 of the outer ring 2 when the roller 4 tilts and rolls at least within the predetermined angular ranges. Thus, the generation of the force effect / constraining force can be prevented. (Second embodiment)

[0058] The groove-orthogonal cross-sectional shape of a ceiling surface 13 of a constant velocity joint 1 of the tripod type of a second embodiment is described below with reference to Fig. 13 to 17. To simplify the description, the difference between the facing distance between the first raceway surface 11 and the second raceway surface 12 and the width of the roller outer peripheral surface 31 in Fig. 13 to 17 are exaggerated. In fact, the difference between the facing distance between the first raceway surface 11 and the second raceway surface 12 and the width of the roller outer peripheral surface 31 is very small.

[0059] In Fig. 13, it is assumed that a torque is transmitted between the roller 4 and the first raceway surface 11. A contour line OL11 obtained by projecting the roller end surface 32 in the axial direction of the outer ring 2 when the roller 4 is inclined by the predetermined inclination angle θp2 and the roller outer peripheral surface 31 comes into contact with the first raceway surface 11 and has a gap from the second raceway surface 12 has a shape indicated by a wide solid line. At this time, the roller 4 is not rolling. In the present embodiment, a part of the contour line OL11 is defined by a boundary line between the circular flat portion 32a and the chamfered portion 32b, and the other part of the contour line OL11 is defined by a boundary line between the chamfered portion 32b and the roller outer peripheral surface 31.A point on the contour line OL11 located on the center axis Lr of the roller 4 and away from the center axis Lo of the outer ring 2 is defined as a first highest central point P11.

[0060] In Fig. 14, it is assumed that a torque is transmitted between the roller 4 and the second raceway surface 12. A contour line OL12 obtained by projecting the roller end surface 32 in the axial direction of the outer ring 2 when the roller 4 is inclined by the predetermined inclination angle θp2 and the roller outer peripheral surface 31 comes into contact with the second raceway surface 12 and has a gap from the first raceway surface 11 has a shape indicated by a wide solid line. At this time, the roller 4 is not rolling. In the present embodiment, a part of the contour line OL12 is defined by a boundary line between the circular flat portion 32a and the chamfered portion 32b, and the other part of the contour line OL12 is defined by a boundary line between the chamfered portion 32b and the roller outer peripheral surface 31.A point on the contour line OL12 located on the center axis Lr of the roller 4 and away from the center axis Lo of the outer ring 2 is defined as a second highest central point P12.

[0061] As in Fig. As shown in Fig. 15, a contour line OL13 obtained by projecting the roller 4 in the axial direction of the outer ring 2 when the joint angle is 0°, the roller 4 rolls in the positive direction by the predetermined rolling angle θr11, and the roller outer peripheral surface 31 comes into contact with the first raceway surface 11 and is spaced from the second raceway surface 12, has a shape indicated by a wide solid line. Therefore, the contour line OL13 is formed by the roller outer peripheral surface 31, the roller end surface 32, and the roller base surface 33. A boundary point on the contour line OL13 between the roller outer peripheral surface 31 and the roller end surface 32, which is located away from the center axis Lo of the outer ring 2, is defined as a highest point P13 of a positive rotation back edge.

[0062] As in Fig. As shown in Fig. 16, a contour line OL14 obtained by projecting the roller 4 in the axial direction of the outer ring 2 when the joint angle is 0°, the roller 4 rolls in the negative direction by the predetermined rolling angle θr12, and the roller outer peripheral surface 31 comes into contact with the second raceway surface 12 and has a gap from the first raceway surface 11, has a shape indicated by a wide solid line. Therefore, the contour line OL14 is formed by the roller outer peripheral surface 31, the roller end surface 32, and the roller base surface 33. A boundary point on the contour line OL14 between the roller outer peripheral surface 31 and the roller end surface 32, which is located away from the center axis Lo of the outer ring 2, is designated as a highest point P14 of a negative rotation back edge.

[0063] As in Fig. As shown in Figure 17, the groove-orthogonal cross-sectional shape of the ceiling surface 13 is a line shape passing through the first highest central point P11, the second highest central point P12, the highest point P13 of the positive twist back edge, and the highest point P14 of the negative twist back edge. Specifically, the groove-orthogonal cross-sectional shape of the ceiling surface 13 is defined by a curved shape 113a connecting the first highest central point P11 and the highest point P14 of the negative twist back edge, a curved shape 113b connecting the second highest central point P12 and the highest point P13 of the positive twist back edge, and a straight shape 113c connecting the first highest central point P11 and the second highest central point P12. Each of the curved shapes 113a, 113b may be defined by an ellipse or a circular arc.

[0064] According to the present embodiment, when the roller outer peripheral surface 31 is in contact with one of the first raceway surface 11 and the second raceway surface 12 and has a gap between them, the groove-orthogonal cross-sectional shape of the ceiling surface 13 can be set to a shape that takes the gap into account. Thus, it is possible to reduce the size and weight of the outer ring 2 while taking the gap into account. (Third embodiment)

[0065] The groove-orthogonal cross-sectional shape of a ceiling surface 13 of a constant velocity joint 1 of the tripod type of a third embodiment is described below with reference to Fig. 18 to 20. In the third embodiment, for the convenience of description, the difference between the facing distance between the first raceway surface 11 and the second raceway surface 12 and the width of the roller outer peripheral surface 31 in Fig. 18 to 20 as exaggerated in the second embodiment.

[0066] As in Fig. As shown in Fig. 18, a contour line OL15 obtained by projecting the roller 4 in the axial direction of the outer ring 2 when the joint angle is 0°, the roller 4 rolls in the positive direction by the predetermined rolling angle θr11, and the roller outer peripheral surface 31 comes into contact with the second raceway surface 12 and has a gap from the first raceway surface 11, has a shape indicated by a wide solid line. Therefore, the contour line OL15 is formed by the roller outer peripheral surface 31, the roller end surface 32, and the roller base surface 33. A boundary point on the contour line OL15 between the roller outer peripheral surface 31 and the roller end surface 32, which is located away from the center axis Lo of the outer ring 2, is defined as a highest point P15 of a positive rotation transmission edge.

[0067] As in Fig. As shown in Fig. 19, a contour line OL16 obtained by projecting the roller 4 in the axial direction of the outer ring 2 when the joint angle is 0°, the roller 4 rolls in the negative direction by the predetermined rolling angle θr12, and the roller outer peripheral surface 31 comes into contact with the first raceway surface 11 and is spaced from the second raceway surface 12, has a shape indicated by a wide solid line. Therefore, the contour line OL16 is formed by the roller outer peripheral surface 31, the roller end surface 32, and the roller base surface 33. A boundary point on the contour line OL16 between the roller outer peripheral surface 31 and the roller end surface 32, which is located away from the center axis Lo of the outer ring 2, is defined as a highest point P16 of a negative rotation transmission edge.

[0068] As in Fig. As shown in Figure 20, the groove-orthogonal cross-sectional shape of the ceiling surface 13 is a line shape passing through the first highest central point P11, the second highest central point P12, the highest point P15 of the positive rotation transmission edge, and the highest point P16 of the negative rotation transmission edge. Specifically, the groove-orthogonal cross-sectional shape of the ceiling surface 13 is defined by a curved shape 213a connecting the first highest central point P11 and the highest point P16 of the negative rotation transmission edge, a curved shape 213b connecting the second highest central point P12 and the highest point P15 of the positive rotation transmission edge, and a straight shape 213c connecting the first highest central point P11 and the second highest central point P12. Each of the curved shapes 213a, 213b may be defined by an ellipse or a circular arc.In the present embodiment, the highest point P13 of the positive twist back edge and the highest point P14 of the negative twist back edge are not used.

[0069] The Fig. The condition shown in Figure 18 may occur if the direction of the torque applied to the outer ring 2 and the tripod 3 is in the Fig. 16 is reversed. The state shown in Fig. The condition shown in Figure 19 may occur if the direction of the torque applied to the outer ring 2 and the tripod 3 is in the Fig. 17 is reversed. The groove-orthogonal cross-sectional shape of the ceiling surface 13 is determined taking such cases into account. Thus, it is possible to reduce the size and weight of the outer ring 2 while taking the clearance into account. (Fourth embodiment)

[0070] The groove-orthogonal cross-sectional shape of a ceiling surface 13 of a constant velocity joint 1 of the tripod type of a fourth embodiment is described below with reference to Fig. 21. In the fourth embodiment, for the convenience of description, the difference between the facing distance between the first raceway surface 11 and the second raceway surface 12 and the width of the roller outer peripheral surface 31 in Fig. 21 as exaggerated in the second and third embodiments.

[0071] As in Fig.21, the groove-orthogonal cross-sectional shape of the ceiling surface 13 is a line shape passing through the first highest central point P11, the second highest central point P12, the highest point of the positive rotation back edge P13, the highest point of the negative rotation back edge P14, the highest point of the positive rotation transmission edge P15, and the highest point of the negative rotation transmission edge P16.

[0072] Specifically, the groove-orthogonal cross-sectional shape of the ceiling surface 13 is defined by a curved shape 313a connecting the first highest central point P11 and the highest point of the negative rotation back edge P14, a curved shape 313b connecting the second highest central point P12 and the highest point P13 of the positive rotation back edge, and a straight shape 313c connecting the first highest central point P11 and the second highest central point P12. Furthermore, the groove-orthogonal cross-sectional shape of the ceiling surface 13 is defined by a curved shape 313d connecting the highest point of the positive rotation back edge P13 and the highest point of the positive rotation transmission edge P15, and a curved shape 313e connecting the highest point of the negative rotation back edge P14 and the highest point of the negative rotation transmission edge P16.Each of the curved shapes 313a, 313b can be defined by an ellipse or a circular arc. According to the present embodiment, it is possible to reduce the size and weight of the outer ring 2 while taking the clearance into account. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] 2016-130533

[0003] JP 2016-130533 A

[0003]

Claims

[1] Constant velocity joint of the tripod type (1), comprising: an outer ring (2) having a plurality of raceway grooves (10) extending in an axial direction; a tripod (3) having a plurality of tripod shaft sections (22) extending radially outward; and Rollers (4) fitted externally onto the tripod shaft sections and designed to roll in the raceway grooves, wherein: the raceway groove has a first raceway surface (11) forming a groove side surface, a second raceway surface (12) forming another groove side surface, and a ceiling surface (13) forming a groove bottom surface; the role has the following: a roller outer peripheral surface (31) designed to roll on the first raceway surface or the second raceway surface, and a roller end surface (32) which is an axial end surface of the roller facing the ceiling surface; a point located on a center axis (Lr) of the roller and away from a center axis (Lo) of the outer ring on a contour line (OL1, OL11, OL12) obtained by projecting the roller end surface in the axial direction of the outer ring when the roller is inclined by a predetermined inclination angle (θp2) is defined as a highest central point (P1, P11, P12); a boundary point between the roller outer peripheral surface and the roller end surface, which is located away from the center axis of the outer ring on a contour line (OL2, OL13, OL15) obtained by projecting the roller in the axial direction of the outer ring when the roller rolls in a positive direction by a predetermined rolling angle (θr11), is defined as a highest point of a positive rotation edge (P2, P13, P15); a boundary point between the roller outer peripheral surface and the roller end surface, which is located away from the center axis of the outer ring on a contour line (OL3, OL14, OL16) obtained by projecting the roller in the axial direction of the outer ring when the roller rolls in a negative direction by a predetermined rolling angle (θr12), is defined as a highest point of a negative rotation edge (P3, P14, P16); and a groove-orthogonal cross-sectional shape of the ceiling surface is a line shape passing through the highest central point (P1, P11, P12), the highest point of the positive turning edge (P2, P13, P15) and the highest point of the negative turning edge (P3, P14, P16). [2] A tripod type constant velocity joint according to claim 1, wherein the groove-orthogonal cross-sectional shape of the ceiling surface is defined by a curved shape (13a, 113a, 213a, 313a) connecting the highest central point and the highest point of the positive rotation edge, and a curved shape (13b, 113b, 213b, 313b) connecting the highest central point and the highest point of the negative rotation edge. [3] A tripod type constant velocity joint according to claim 1 or 2, wherein: the highest central point (P11, P12) has the following: a first highest central point (P11) which is a point located on the center axis of the roller and away from the center axis of the outer ring on a contour line (OL11) obtained by projecting the roller end surface in the axial direction of the outer ring when the roller is inclined by the predetermined inclination angle and the roller outer peripheral surface comes into contact with the first raceway surface and has a gap from the second raceway surface, and a second highest central point (P12) which is a point located on the center axis of the roller and away from the center axis of the outer ring on a contour line (OL12) obtained by projecting the roller end surface in the axial direction of the outer ring when the roller is inclined by the predetermined inclination angle and the roller outer peripheral surface comes into contact with the second raceway surface and has a gap from the first raceway surface; the highest point of the positive rotation edge (P13) has a highest point of a positive rotation back edge (P13), which is a boundary point between the roller outer peripheral surface on the second raceway surface side and the roller end surface and is located away from the center axis of the outer ring on a contour line (OL13) obtained by projecting the roller in the axial direction of the outer ring when the roller rolls in the positive direction by the predetermined rolling angle and the roller outer peripheral surface comes into contact with the first raceway surface and has the clearance from the second raceway surface; the highest point of the negative rotation edge (P14) comprises a highest point of a negative rotation back edge (P14), which is a boundary point between the roller outer peripheral surface on the first raceway surface side and the roller end surface and is located away from the center axis of the outer ring on a contour line (OL14) obtained by projecting the roller in the axial direction of the outer ring when the roller rolls in the negative direction by the predetermined rolling angle and the roller outer peripheral surface comes into contact with the second raceway surface and has the clearance from the first raceway surface; and the groove-orthogonal cross-sectional shape of the ceiling surface is a line shape passing through the first highest central point (P11), the second highest central point (P12), the highest point of the positive rotation back edge (P13) and the highest point of the negative rotation back edge (P14). [4] A tripod type constant velocity joint according to claim 3, wherein the groove-orthogonal cross-sectional shape of the ceiling surface is defined by: a curved shape (113a) connecting the first highest central point and the highest point of the negative twist back edge; a curved shape (113b) connecting the second highest central point and the highest point of the positive twist back edge; and a straight shape (113c) connecting the first highest central point and the second highest central point. [5] A tripod type constant velocity joint according to claim 1 or 2, wherein: the highest central point (P11) has the following: a first highest central point (P11) which is a point located on the center axis of the roller and away from the center axis of the outer ring on a contour line (OL11) obtained by projecting the roller end surface in the axial direction of the outer ring when the roller is inclined by the predetermined inclination angle and the roller outer peripheral surface comes into contact with the first raceway surface and has a gap from the second raceway surface, and a second highest central point (P12) which is a point located on the center axis of the roller and away from the center axis of the outer ring on a contour line (OL12) obtained by projecting the roller end surface in the axial direction of the outer ring when the roller is inclined by the predetermined inclination angle and the roller outer peripheral surface comes into contact with the second raceway surface and has a gap from the first raceway surface; the highest point of the positive rotation edge (P15) comprises a highest point of a positive rotation transmission edge (P15) which is a boundary point between the roller outer peripheral surface on the second raceway surface side and the roller end surface and is located away from the center axis of the outer ring on a contour line (OL15) obtained by projecting the roller in the axial direction of the outer ring when the roller rolls in the positive direction by the predetermined rolling angle and the roller outer peripheral surface comes into contact with the second raceway surface and has the clearance from the first raceway surface; the highest point of the negative rotation edge (P16) comprises a highest point of a negative rotation transmission edge (P16) which is a boundary point between the roller outer peripheral surface on the side of the first raceway surface and the roller end surface and is located away from the center axis of the outer ring on a contour line (OL16) obtained by projecting the roller in the axial direction of the outer ring when the roller rolls in the negative direction by the predetermined rolling angle and the roller outer peripheral surface comes into contact with the first raceway surface and has the clearance from the second raceway surface; and the groove-orthogonal cross-sectional shape of the ceiling surface is a line shape passing through the first highest central point (P11), the second highest central point (P12), the highest point of the positive rotation transmission edge (P15) and the highest point of the negative rotation transmission edge (P16). [6] A tripod type constant velocity joint according to claim 5, wherein the groove-orthogonal cross-sectional shape of the ceiling surface is defined by: a curved shape (213a) connecting the first highest central point and the highest point of the negative rotation transmission edge; a curved shape (213b) connecting the second highest central point and the highest point of the positive rotation transmission edge; and a straight shape (213c) connecting the first highest central point and the second highest central point. [7] A tripod type constant velocity joint according to claim 3 or 4, wherein: the highest point of the positive rotation edge (P15) further comprises a highest point of a positive rotation transmission edge (P15) which is a boundary point between the roller outer peripheral surface on the second raceway surface side and the roller end surface and is located away from the center axis of the outer ring on a contour line (OL15) obtained by projecting the roller in the axial direction of the outer ring when the roller rolls in the positive direction by the predetermined rolling angle and the roller outer peripheral surface comes into contact with the second raceway surface and has the clearance from the first raceway surface; the highest point of the negative rotation edge (P16) further comprises a highest point of a negative rotation transmission edge (P16), which is a boundary point between the roller outer peripheral surface on the side of the first raceway surface and the roller end surface and is located away from the center axis of the outer ring on a contour line (OL16) obtained by projecting the roller in the axial direction of the outer ring when the roller rolls in the negative direction by the predetermined rolling angle and the roller outer peripheral surface comes into contact with the first raceway surface and has the clearance from the second raceway surface; and the groove-orthogonal cross-sectional shape of the ceiling surface is a line shape passing through the first highest central point (P11), the second highest central point (P12), the highest point of the positive rotation back edge (P13), the highest point of the negative rotation back edge (P14), the highest point of the positive rotation transmission edge (P15) and the highest point of the negative rotation transmission edge (P16). [8] A tripod type constant velocity joint according to claim 7, wherein the groove-orthogonal cross-sectional shape of the ceiling surface is defined by: a curved shape (313a) connecting the first highest central point and the highest point of the negative twist back edge; a curved shape (313b) connecting the second highest central point and the highest point of the positive twist back edge; a straight shape (313c) connecting the first highest central point and the second highest central point; a line shape (313d) connecting the highest point of the negative rotation back edge and the highest point of the negative rotation transmission edge; and a line shape (313e) connecting the highest point of the positive rotation back edge and the highest point of the positive rotation transfer edge. [9] A tripod type constant velocity joint according to any one of claims 1 to 8, wherein the predetermined inclination angle is an angle (φ1) which is greater than a maximum joint angle of the tripod type constant velocity joint during straight travel of a vehicle at a constant speed; and the predetermined rolling angle is an angle which is greater than a maximum rolling angle (φ11) of the roller during straight-line travel of the vehicle at the constant speed. [10] A tripod type constant velocity joint according to claim 9, wherein: the maximum joint angle (φ1) of the tripod type constant velocity joint during straight-ahead travel of the vehicle at constant speed is an angle within a range of 4 to 10°; and the maximum rolling angle (φ11) of the roller during straight-line travel of the vehicle at constant speed is an angle lying in a range of 0 to 5°. [11] A tripod type constant velocity joint according to claim 9 or 10, wherein: the predetermined inclination angle is an angle which is greater than a maximum joint angle (φ2) of the tripod-type constant velocity joint during acceleration or deceleration of the straight-ahead vehicle; and the predetermined rolling angle is an angle that is greater than a maximum rolling angle (φ12) of the roller during acceleration or deceleration of the straight-ahead vehicle. [12] A tripod type constant velocity joint according to claim 9 or 10, wherein: the predetermined inclination angle is an angle equal to or smaller than a maximum joint angle (φ2) of the tripod type constant velocity joint during acceleration or deceleration of the straight-ahead vehicle; and the predetermined rolling angle is an angle equal to or smaller than a maximum rolling angle (φ12) of the roller during acceleration or deceleration of the straight-ahead vehicle. [13] A tripod type constant velocity joint according to claim 11 or 12, wherein: the maximum joint angle (φ2) of the tripod type constant velocity joint during acceleration or deceleration of the vehicle traveling straight ahead is an angle within a range of 6 to 20°; and the maximum rolling angle (φ12) of the roller during acceleration or deceleration of the straight-ahead vehicle is an angle in a range of 0 to 5°. [14] A tripod type constant velocity joint according to any one of claims 1 to 13, wherein: the predetermined inclination angle is an angle which is smaller than a maximum joint angle (φ3) of the tripod type constant velocity joint during maximum steering; and the predetermined rolling angle is an angle smaller than a maximum rolling angle (φ13) of the roller during maximum steering. [15] A tripod type constant velocity joint according to claim 14, wherein: the maximum joint angle (φ3) of the tripod type constant velocity joint during maximum steering is an angle within a range of 10 to 25°; and the maximum rolling angle (φ13) of the roller during maximum steering is an angle ranging from 0 to 10°. [16] A tripod type constant velocity joint according to any one of claims 1 to 15, wherein the roller is fitted externally to the tripod shaft portion such that the roller is tiltable with respect to the tripod shaft portion.

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